Repeated washing of garments, particularly those comprising cotton or other cellulosic fibres, causes gradual loss of material from individual fibres and the loss of whole fibres from the fabric. These processes of attrition result in thinning of the fabric, eventually rendering it semi-transparent, more prone to accidental tearing and generally detracting from its original appearance.
Hitherto, there has been no way of minimising this kind of damage except by employing less frequent washing and use of less harsh detergent products and/or wash conditions, which obviously tends to less effective cleaning.
In laundry cleaning or treatment products, it is essential for some ingredients to be deposited onto and adhere to the fabric for them to deliver their beneficial effects. Typical examples are fabric conditioners or softeners. Nevertheless, the benefits conferred by such conventional materials do not include rebuilding the fabric.
It has now been found possible to include in laundry products, agents which deposit cellulose or cellulose-like materials onto the fabric to at least partially replace the lost material of the fibre.
EP-A-0 084 772 discloses a graft polymer dispersion comprising a vinyl-containing organopolysiloxane, an organopolysiloxane with unsubstituted silicon atom and polymerised units of vinyl monomers. Aqueous emulsions of these materials are used as water repellents to be applied to textiles during manufacture, whilst also endowing a softening and smoothing effect. Unlike conventional silicones they are said to offer the advantage of retaining elasticity and "recovery" of the weave. There is also a disclosure of strengthening of textiles during manufacture by application of acrylates, polyacrylates and polymetacrylates. However, there is nothing in this reference to suggest use of a material during a laundry process, for rebuilding the material of the fabric.
EP-A-0 025 255 discloses laundry wash or softening agents and shampoo compositions, containing a complex of an arylamine and a fatty acid or phosphate ester. The heat of the wash/rinse water softens the solid particles of this material to enhance its deposition. However, again, there is no suggestion of this agent being able to rebuild cellulose-type fibres.
EP-A-0 266 324 discloses fabric conditioners which are amine-anionic surfactant ion pair complexes. Thus, these are not polymeric, nor do they aid fabric rebuild.
WO-A-98/00500 discloses detergent compositions comprising a peptide or protein deposition aid having a high affinity for fibres or a surface, and having a benefit agent attached/absorbed to the deposition aid. There is no disclosure of use for these materials as fabric rebuild agents. Moreover, the peptide/protein material is significantly more costly than the polysaccharides used in the present invention.
WO-A-98/29528 discloses cellulose ethers in which some substituents are (poly)alkoxylated, analogues of the latter in which the (poly)alkoxylated groups are terminated with a cationic moiety in the form of a quaternary ammonium group, and cellulose ethers in which some substituents are carboxylic acids in the salt form (i.e. the materials are essentially carboxymethylcellulose variants). None of these substituents in any variant is of a kind which would undergo a chemical change to enhance fabric affinity.
WO-A-99/14245 discloses laundry detergent compositions containing cellulosic based polymers to provide appearance and integrity benefits to fabrics. These polymers are cellulosic polymers in which the saccharide rings have pendant oxygen atoms to which substituents `R` are bonded, i.e. they are attached to the rings via an ether linkage. The groups `R` can be hydrogen, lower alkyl or alkylene linkages terminated by carboxylic acid, ester or amide groups. Optionally, up to five alkyleneoxy groups may be interspersed between the groups are the respective oxygen atom. At least some of these groups may undergo a chemical change such as hydrolysis, in the wash liquor. However no such change would result in an increased affinity for the fabric. On the contrary, because the "ester" group is configured with the carbonyl group closer to the polysaccharide than the oxygen atom (i.e. esters of carboxyalkyl groups), any hydrolysis will result in free acid substituents which will actually result in an increase in solubility and therefore, a decrease in affinity for the fabric.
WO-A-99/14295 discloses structures analogous to those described in WO-A-99/14245 but in one alternative, the substituents `R` together with the oxygen on the saccharide ring, constitute pendant half-esters of certain dicarboxylic acids. A single example of such a material is given. The dicarboxylic acid half-esters would tend to hydrolyse in the wash liquor and thereby increase affinity of the material for a cotton fabric. However, first, this mechanism of action or behaviour is not mentioned. Second, the hydrolysis rate of such dicarboxylic acids half esters is not as great as that of esters of monocarboxylic acids (which are not disclosed or claimed in WO-A-99/14295). Third, the degree of substitution for this variant is specified as being from 0.001 to 0.1. This is so low as to make the enhancement of fabric affinity too low to be worthwhile for this mechanism of action. Fourth, the structures described and claimed insofar as they have such half ester substituents, must also have substituents of the type which are carboxyalkyl groups or esters thereof, i.e. of the type also described in WO-A-99/14245. In the latter (ester) case, these would hydrolyse to the free acid form. The degree of substitution of the latter (0.2 to 2) is considerably higher than for the half-ester groups and the resultant increase in solubility would easily negate any enhanced affinity for the fabric by hydrolysis of the half-ester groups.